The present invention is directed toward a flexible bulk container and more particularly toward such a container which includes normally raised lifting strap loops which can be engaged by the forks of a forklift truck and which containers can be stacked one on top of the other without interfering with the lifting loops of the container below.
Large flexible fabric bags for containing and transporting granular or powdered bulk material have been used for many years and their use is becoming increasingly more popular. This is primarily due to their relatively low cost and to the fact that when the bags are empty, they take up very little space and are relatively light.
When filled, the flexible bulk containers may carry a cubic meter or more of material and may weigh in excess of two tons. Straps are normally provided and are securely fastened to the bags adjacent the top thereof to form lifting loops which can cooperate with the forks of a forklift truck or other lifting device when it becomes necessary to transport a full bag. Containers of this type are shown, for example, in U.S. Pat. Nos. 4,010,784; 4,207,937; 4,300,608; 4,301,848 and in British Application No. GB 2,063,816 A published June 10, 1981.
The lifting straps or loops of prior art containers have primarily been comprised of a flexible material. Thus, when it was desired to lift a prior art bag utilizing the tongs of a forklift truck, it was usually necessary for a second worker to hold the loops in an upright, open position so that the tongs could be inserted therethrough. Two workers were, therefore, required thus increasing the costs of transportation.
Attempts have been made to provide loops which include stiffening members therein so as to maintain the loop in an upward and open position. In this way, a single worker operating the lift truck could insert the tongs of the forklift through the loops without the aid of a second worker. Examples of such self-sustaining loops are described in U.S. Pat. No. 4,300,608 and published British Application No. 2,063,816 A.
It is common to stack filled containers on top of each other for storage purposes and, for this reason, the lifting loops in the last two mentioned prior art documents are constructed in such a way that they collapse under the weight of the container above but are designed to recover to an upright, open position when the stacking force is removed. It has been found, however, that these loops do not always recover particularly after they have been used a number of times and it has been found that a second worker is needed to reopen and align the loops so that the container can be lifted by a forklift truck.